Along with the 55 pound bag of Crisp #19 maris otter I got recently I also got 19 ounces of British hops and 11 pounds of specialty grains. I’m all set for a year’s worth of session beer at my three gallons a.month brewing rate.
It’s a good feeling to be stocked up.
This 
You can make more beer and bottle condition them in your basement. I do that all the time with my stouts, porters etc. I would find it hard to let all those supplies just sit there.
Once a month suits my needs.
Same here. I do keep the equivalent of a small homebrew shop worth of ingredients on hand, but that’s because I often brew on short notice and don’t have a LHBS that is convenient to me. It’s peace of mind that I can brew an IPA, a porter, a lager, or pretty much anything else with what I have on hand and not needing to scramble to get ingredients from a store.
When I stock up on anything, as soon as I place the order, I realize I want to start using something else.